The present invention relates generally to reducing the effect of stress in humans and animals and especially production animals and, more specifically, to the feeding of a combination of zinc and butyric acid for the treatment or amelioration of enteric stress from heat stress or disease stress.
High summer temperatures result in enormous amounts of physiological stress to production animals, leading to decreased feed intake, decreased growth rate and decreased feed conversion. During periods of rapid increasing temperature and humidity (expressed as a high humidity index (HI)), animals adjust to the increasing HI over a period of weeks. During this period, stress from HI to the animal causes the body core temperature to rise, resulting in an increase of the blood flow from the organs to the skin of the animal which allows for rapid cooling of the inner body core. Once the HI reaches a specific threshold, the animal is no longer able to effectively dissipate heat from the body core. This causes the animal's systemic blood flow to be diverted to the peripheral tissues to mitigate the heat stress, which leads to decreased blood flow to the intestine. These heat stressed animals are not in a position to consume any feed. The resulting decreased feed intake combined with lower blood flow to the intestine leads to villi damage, a decreased absorptive area for nutrients and sloughing of the intestinal epithelial cells. All of these combined effects result in a loss of intestinal integrity.
Swine encounter multiple pathogens throughout their life including viruses, bacteria, fungi and parasites. Any infection during the early life stages, particularly in nursery and early weaned piglets, can cause severe morbidity and mortality. It is difficult to predict the occurrence of any such event, and any disease outbreak results in severe economic losses. Therefore, it is important to develop strategies for these health challenges to decrease the mortality, maintain the growth of the animals and mitigate the losses. Most infections of agricultural animals occur through the gastrointestinal (GI) route. One example of such infection with huge economic potential is porcine epidemic diarrhea virus (PEDV). The PEDV coronavirus infects the enterocytes of the small intestine, resulting in severe inflammation of the gastrointestinal tract leading to diarrhea and decreased nutrient and water absorption. In suckling pigs, a severe PEDV infection commonly results in mortality. In newly weaned pigs, clinical signs lasts for approximately 7-14 days. Clinical signs include: decreased feed intake, decreased tissue accretion, and diarrhea; however, mortality is rarely observed. Because the animal's growth is affected significantly, they never regain their growth potential and it leads to huge economic losses to the producers.
The pathogenesis of any enteric disease is complex and involves different cellular pathways. These include inflammatory and immune signaling, oxidative stress, energy sensing, osmotic and microbial homeostasis pathways. Compounds which can counteract one or more of these pathways have the potential to mitigate the severity or prevent the negative effects of gastrointestinal infections. Additionally, compounds that augment intestinal restitution and recovery can reduce the impact that enteric pathogens may have on intestinal function and integrity, pig performance, wellbeing and may help the animals regain their growth potential.
Heat stress, infection with enteric viruses or bacteria will increase the permeability of the intestinal cells. This allows bacterial compounds such as lipopolysaccharide (LPS) and/or other noxious substances from the intestinal lumen to get through the intestinal barrier and cause an unwarranted inflammatory and immune response in animals. Compounds that improve or sustain intestinal integrity can decrease the effect of heat stress or disease challenges on intestinal integrity and can improve the growth of the animals during heat stress or infection.